The present invention relates to a capacitor termination and method for making same.
Presently known techniques for forming a cathode termination on a capacitor often result in off center cathode termination surfaces. These off center terminations can result in inconsistencies in the performance of the capacitors and is undesirable.
Therefore a primary object of the present invention is the provision of an improved capacitor termination and method for making same which permits the molding of a protective material around the capacitor pellet with a substantially uniform thickness.
A further object of the present invention is the provision of an improved capacitor termination and method for making same which results in a cathode termination that is centered with respect to the capacitor body.
A further object of the present invention is the provision of an improved capacitor having a low ESR.
A further object of the present invention is the provision of an improved capacitor termination and method for making same which is economical, efficient in operation, and simple in operation.
The foregoing objects may be achieved by a capacitor comprising a capacitor pellet having an anode end a cathode end, a front face, a rear face, first and second opposite sides, and a longitudinal pellet axis extending from the cathode end to the anode end. An anode wire is connected to and in contact with the pellet and extends outwardly from the anode end of the pellet. A quantity of conductive material is in electrical contact with the cathode end of the capacitor pellet. A molded material covers the pellet with a substantially uniform thickness and also covers a portion of the conductive material at the anode end of the pellet. The molded protective material leaves a portion of the conductive material uncovered to create and expose a cathode termination at the cathode end of the pellet. The cathode termination is approximately centered on the longitudinal axis of the pellet and faces axially away from the cathode end of the pellet. A cathode terminal covers and is in electrical contact with the cathode termination.
The method of the present invention comprises forming a capacitor pellet having a pellet anode end, a pellet cathode end, a pellet front wall, a pellet rear wall, first and second opposite pellet side walls, and a longitudinal axis extending between the pellet anode and cathode ends. An anode wire is connected to and extends from the anode end of the pellet. A fluid conductive material capable of hardening is applied to the cathode end and portions of the pellet front wall, rear wall, first side wall and second side wall adjacent the cathode end of the pellet. The fluid conductive material creates a tear drop shaped conductive body having a tear drop point extending axially away from the cathode end of the pellet. The fluid conductive material is permitted to harden. A protective material is molded around the pellet and the conductive material to form a protective coating. A portion of the tear drop point and the protective coating are then removed to form an exposed cathode termination surface of the conductive body.
According to another feature of the invention the removing step further comprises forming the cathode termination surface into a flat surface facing axially away from the pellet cathode end.
According to another feature of the invention the removing step is accomplished by cutting or by grinding the tear drop point.